Laser probe tip fiber cap cleaning

ABSTRACT

A system for cleaning a fiber cap including a first fixture configured to hold the fiber cap, the fiber cap having an internal cavity with an opening therein. The fiber cap also includes a first axis generally aligned with the central axis of the fiber cap and internal cavity, a second axis orthogonal to the first axis, and a third axis orthogonal to the first and second axes. The system further includes a second fixture configured to hold a particulate collecting member (1) to receive and hold an electrical charge and (2) for insertion into the opening of the fiber cap. Also included with the system is a first camera positioned to provide a view of the fiber cap held in the first fixture and the particulate collecting member held in the second fixture in the direction of the third axis of the fiber cap and a second camera positioned to provide a view of the fiber cap held in the first fixture and the particulate collecting member held in the second fixture in the direction of the second axis of the fiber cap.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims the benefit of U.S.provisional patent application Ser. No. 61/423,279, filed Dec. 15, 2010,the content of which is hereby incorporated by reference in itsentirety.

FIELD

Embodiments of the invention are directed to a method of cleaning afiber cap of a laser probe tip and, more specifically, to a method ofelectrostatically cleaning a fiber cap.

BACKGROUND

Medical lasers have been used in various practice areas, such as, forexample, urology, neurology, otorhinolaryngology, general anestheticophthalmology, dentistry, gastroenterology, cardiology, gynecology, andthoracic and orthopedic procedures. Generally, these procedures requireprecisely controlled delivery of energy as part of the treatmentprotocol.

Surgical laser systems utilize a frequency doubled Nd:YAG laser, whichoperates at 532 nm in a quasi continuous mode at high power levels(e.g., 100 watts) and has been used to efficiently ablate tissue. Thefrequency doubled Nd:YAG laser can be pumped by CW krypton arc lamps andcan produce a constant train of laser light pulses. When ablative powerdensities are used, a superficial layer of denatured tissue is leftbehind. At high powers, 532 nm lasers induce a superficial char layerthat strongly absorbs the laser light and improves ablation efficiency.

Many surgical laser procedures utilize a surgical probe, which generallycomprises an optical fiber and a fiber cap over a distal end of theoptical fiber to form a probe tip. A laser source delivers laser energythrough the optical fiber to the probe tip where the energy isdischarged through the fiber cap and onto desired portions of thetargeted tissue.

The laser energy may be directed laterally from the probe tip byreflecting the laser energy off a polished beveled surface at the distalend of the optical fiber. The fiber cap seals a cavity containing a gas(or vacuum) that maintains the necessary refractive index difference fortotal internal reflection at the beveled surface.

It is important that the fiber cap be free of contaminants on the wallsof the interior cavity of the fiber cap that receives the distal end ofthe optical fiber. Such contaminates can adversely affect the assemblyof the probe tip and can lead to failure of the probe tip.

SUMMARY

Embodiments of the invention are directed to a method of cleaning afiber cap of a laser probe tip and a method of manufacturing a laserprobe tip. In one embodiment of the method, a glass fiber comprising acap body having an internal cavity and an opening to the cavity at aproximal end is provided. A particulate collecting member is alsoprovided. An electrical charge is applied to the particulate collectingmember. A distal end of the particulate collecting member is theninserted through the opening and into the cavity of the fiber cap.Particles located within the cavity are attracted to the particulatecollecting member. The attracted particles attach to the particulatecollecting member. The particulate collecting member is then removedfrom the cavity.

In one embodiment of manufacturing a laser probe tip, an optical fiberhaving a distal end is provided. A glass fiber cap comprising a cap bodyhaving an internal cavity and an opening to the cavity at a proximal endis provided. Particles having a first electrical charge are containedwithin the cavity. A particulate collecting member is also provided andan electrical charge is applied to the member. The particulatecollecting member is inserted through the opening and into the cavity ofthe fiber cap. The particles are attracted to the member responsive toinserting the member into the cavity. The attracted particles attach tothe member. The member and the attached particles are then removed fromthe cavity. The distal end of the optical fiber is then inserted throughthe opening and into the cavity of the fiber cap. The fiber cap is thenattached to the distal end of the optical fiber.

Other features and benefits that characterize embodiments of the presentdisclosure will be apparent upon reading the following detaileddescription and review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block drawing of an exemplary surgical lasersystem in accordance with embodiments of the invention.

FIG. 2 is a flowchart illustrating a method of cleaning a fiber cap inaccordance with embodiments of the invention.

FIGS. 3-5 are simplified side cross-sectional views of a fiber cap and aparticulate cleaning member illustrating steps of the fiber cap cleaningmethod.

FIGS. 6A and 6B respectively are simplified top and side views ofembodiments of an apparatus used to assist in the performance of methodsteps.

FIG. 7 is an isometric view of an exemplary probe tip in accordance withembodiments of the invention.

FIG. 8 is a side cross-sectional view of the exemplary probe tip of FIG.7 taken generally along line 8-8.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments of the invention are directed to a method of cleaning afiber cap of a laser probe tip and a method of manufacturing a laserprobe tip.

FIG. 1 is a simplified diagram of an exemplary surgical laser system 100with which a laser probe tip 101 formed in accordance with embodimentsof the invention may be used. In general, the laser system 100 isconfigured to generate electromagnetic radiation 102 in the form of alaser beam, deliver the electromagnetic radiation through a waveguide oroptical fiber 104 to the probe tip 101 where it is discharged to adesired target, such as tissue of a patient.

The exemplary system 100 comprises a laser resonator 108. The laserresonator 108 may include a first resonator minor 110, a secondresonator minor 112 and a laser rod or element 114. In one embodiment,the laser element 114 comprises a yttrium-aluminum-garnet crystal rodwith neodymium atoms dispersed in the YAG rod to form a Nd:YAG laserelement. Other conventional laser elements 114 may also be used.

The laser element 114 is pumped by a light input 116 from an opticalpump source 118, such as a Kr arc lamp or other conventional pumpsource, to produce laser light or beam 120 at a first frequency. Thelaser resonator 108 also includes a nonlinear crystal 122, such as alithium borate (LBO) crystal or a potassium titanyl phosphate crystal(KTP), for generating a second harmonic of the laser beam 120 emitted bythe laser element 114. The laser beam 120 inside the resonator 108bounces back and forth between the first and second resonator minors 110and 112, reflects off a folding minor 124 and propagates through thelaser element 114 and nonlinear crystal 122. The laser element 114 hasoptical gain at a certain wavelength and this determines the wavelengthof the laser beam 120 inside the resonator 108. This wavelength is alsoreferred to as the fundamental wavelength. For the Nd:YAG laser element114, the fundamental wavelength is 1004 nm.

A Q-switch 131 may be used in the resonator 108 to convert the laserbeam 120 to a train of short pulses with high peak power. These shortpulses increase the conversion efficiency of the second harmonic laserbeam 102 and increase the average power of the laser beam 102 outsidethe resonator 108.

When the laser beam 120 inside the resonator 108 propagates through thenonlinear crystal 122 in a direction away from the folding minor 124 andtoward the second resonator minor 112, a beam 102 of electromagneticradiation at the second harmonic wavelength is output from the crystal122. The second resonator minor 112 is highly reflective at both thefundamental and second harmonic wavelengths, and both beams 120 and 102propagate back through the nonlinear crystal 122. On this second pass,more beams 102 at the second harmonic wavelength are produced. Forexample, the nonlinear crystal 122 can produce a laser beam 102 having awavelength of approximately 532 nm (green) when a Nd:YAG rod is used asthe laser element 114. One advantage of the 532 nm wavelength is that itis strongly absorbed by hemoglobin in blood and, therefore, is usefulfor cutting, vaporizing and coagulating vascular tissue.

The folding minor 124 is highly reflective at the fundamental wavelengthand is highly transmissive at the second harmonic wavelength. Thus, thelaser beam 102 at the second harmonic passes through the folding minor124 and produces a second harmonic laser beam 102 outside the opticalresonator 108. The optical fiber 104 connects to an optical coupler 126,which couples the beam 102 to the optical fiber 102. The beam 102travels to the optical fiber 102 to a laser delivery probe 128 coupledto a distal end 130 of the optical fiber 104. In one embodiment, theprobe 128 supports the optical fiber 104 and the probe tip 101 duringsurgical laser treatments where the beam 102 is delivered to targetedtissue of a patient through the probe tip 101. In one embodiment, theprobe 128 includes an endoscope or cystoscope.

The probe tip 101 generally comprises a fiber cap that is attached tothe distal end of the optical fiber 104. Embodiments of the inventionare directed to methods of cleaning the fiber cap prior to itsattachment to the optical fiber 104 during the manufacture of the probetip 101. FIG. 2 is a flowchart illustrating a method of cleaning a fibercap in accordance with embodiments of the invention. FIGS. 3-5 aresimplified side cross-sectional views of steps of the fiber cap cleaningprocess in accordance with embodiments of the invention.

At step 132 of the method, a fiber cap 134 comprising a cap body 136having an internal cavity 138 and an opening 140 to the cavity 138 at aproximal end 142 is provided, as shown in FIG. 3. In one embodiment, thefiber cap 134 is formed of fused silica glass. In one embodiment, thefiber cap 134 includes a cap body 136 having an interior cavity 138 andan opening 140 to the interior cavity 138 at a proximal end 142, asshown in FIG. 3. While a distal end 143 of the fiber cap 134 isillustrated as being closed, embodiments of the fiber cap 134 include anopen distal end 143, which may be fused closed during manufacture of theprobe tip 101.

In one embodiment, the fiber cap 134 has an electrostatic charge thatattracts particles 144 within the interior cavity 138. The electrostaticcharge on the fiber cap 134 generally causes the particles 144 to attachto the interior surface 145 that defines the interior cavity 138, asshown in FIG. 3. Embodiments of the invention are directed to methods ofremoving the particles 144 from within the interior cavity 138 of thefiber cap 134 before attaching the fiber cap 134 to the optical fiber104.

At 146, a particulate collecting member 147 is provided. In oneembodiment, the particulate collecting member 147 is in the form of anelectrical insulator. Embodiments of the electrical insulator includeglass, ceramic, porcelain and composite polymer materials. In oneembodiment, the particulate collecting member 147 is in the form of arod, a wire, a fiber, or woven fibers.

At 148, an electrical charge is applied to the particulate collectingmember 147. In one embodiment, the electrical charge is applied to themember 147 by rubbing the particulate collecting member 147 with glassfibers or other suitable material. In accordance with anotherembodiment, step 148 involves applying an electrical charge to theparticulate collecting member 147 using an electronic device, such as adevice comprising DC power supplier or DC voltage source. The chargeapplied to the particulate collecting member 147 is generally identicalto that typically electrostatically generated on the fiber cap 134.

At step 150 of the method, the particulate collecting member 147 isinserted through the opening 140 of the fiber cap 134 and into thecavity 138, as shown in FIG. 4. In one embodiment, the particulatecollecting member 147 has a width that is slightly smaller than theopening 140 of the fiber cap 134. In one embodiment, the opening 140 hasa diameter of less than 2 millimeters. In one embodiment of theinserting step 150, the distal end 160 of the particulate collectingmember 147 is first aligned with the opening 140 to the fiber cap 134,such that a longitudinal axis 151 of the member 147 is generally alignedparallel with a central axis 152 of the fiber cap 134, as shown in FIG.3. Once aligned, the distal end 160 of the particulate collecting member147 is inserted into the cavity 138 of the fiber cap 134, as shown inFIG. 4.

At step 153 of the method, the particles 144 located within the cavity138 of the fiber cap 134 are attracted to the particulate collectingmember 147. The particles 144 are attracted to the member 147 becausethe particles 144 have an electrostatic charge that is opposite theelectrostatic charge applied to the particulate collecting member 147 instep 148. It is also understood that the particles 144 could have aneutral charge and still be attracted to the member 147 if their chargeis polarized. In one embodiment, while the electrostatic charge appliedto the particulate collecting member 147 is the same polarity as theelectrostatic charge on the fiber cap 134, the magnitude ofelectrostatic charge on the member 147 is greater than that on the fibercap 134. As a result, the particles 144 have a greater attraction to theparticulate collecting member 147 than the walls 145 of the fiber cap134. Thus, the attracted particles 144 become attached to theparticulate collecting member 147 due to the opposing electrostaticcharges.

At 154, the particulate collecting member 147 is removed from theinterior cavity 138 of the fiber cap 134, as shown in FIG. 5. Thisremoval of the member 147 carries the attached particles 144 out of thefiber cap 134. Thus, embodiments of the method operate to remove theparticles 144 from within the interior cavity 138 of the fiber cap 134.The fiber cap 134 cleaned of the particles 144 is ready for attachmentto the distal end 130 of the optical fiber 104.

FIGS. 6A and 6B respectively are simplified top and side views of anapparatus 170 used to assist in the performance of the inserting step150. In one embodiment, the apparatus 170 comprises a fixture 172 thatsupports the fiber cap 134 and a fixture 174 that supports theparticulate collecting member 147. In one embodiment, the fiber cap 134extends from the fixture 172 toward the member 147 that extends from thefixture 174. In one embodiment, the relative positions of the fixtures172 and 174 can be adjusted along a first axis 176 that is generallyaligned with the central axis 152 of the fiber cap 134 and the axis 151of the member 147, an axis 178 that is orthogonal to the axis 176, andan axis 180 that is orthogonal to both the axes 176 and 178. The fixture172 and/or the fixture 174 is moved along the axes 176, 178 and 180relative to the other fixture to align the distal end 160 of theparticulate collecting member 147 with the opening 140 and thelongitudinal axis 151 of the member 147 with the central axis 152 of thefiber cap 134. Once aligned, the distal end 162 of the particulatecollecting member 147 is then inserted into the cavity 138 of the fibercap 134 by moving at least one of the fixtures 172 or 174 toward theother along the axis 176 to complete step 150 of the method.

Accordingly, one embodiment of the method step 150 comprises holding thefiber cap 134 in the fixture 172 and holding the particulate collectingmember 147 in the fixture 174. Next, the longitudinal axis 151 of theparticulate collecting member 147 is aligned with the central axis 152of the cavity 138 of the fiber cap 134. Finally, the distal end 162 ofthe particulate collecting member 147 is inserted through the opening140 and into the cavity 138 of the fiber cap 134 by moving the fixture174 relative to the fixture 172 along the axis 176 to complete methodstep 150, as shown in FIG. 4.

In one embodiment, the apparatus 170 includes a pair of cameras 180(FIG. 6A) and 182 (FIG. 6B) that assist in aligning the distal end 160of the particulate collecting member 147 with the opening 140. In oneembodiment, the camera 180 is positioned to provide a magnified view ofthe proximal end 142 of the fiber cap 134 and the distal end 160 of theparticulate collecting member 147 along the direction of the axis 178.The camera 182 is configured to provide a user with a magnified view ofthe proximal end 142 of the fiber cap 134 and the distal end 162 of theparticulate collecting member 147 in the direction of the axis 180. Theviews from the cameras 180 and 182 are preferably provided on one ormore displays (not shown) for the user.

While viewing the images produced by the cameras 180 and 182, a user canadjust the relative positions of the fixtures 172 and 174 along the axes176, 178 and 180 to align the particulate collecting member 147 to thefiber cap 134. Once the member 147 is properly aligned, the fixtures 172and 174 are moved relative to each other along the axis 176 to insertthe distal end 162 of the particulate collecting member 147 into thecavity 138 of the fiber cap 134 to complete the method step 150, asshown in FIG. 4.

The removal of the particles 144 from the interior cavity 138 of thefiber cap 134 prepares the fiber cap 134 for attachment to the distalend 130 of the optical fiber 104, as shown in the isometric view of anexemplary probe tip 101 provided in FIG. 7. FIG. 8 is a sidecross-sectional view of the exemplary probe tip 101 shown in FIG. 7taken generally along line 8-8.

The exemplary optical fiber 104 shown in FIG. 8 generally comprises anylon jacket 190, a buffer or hard cladding 192, cladding 194 and anoptical fiber core 196. It is understood that other forms of opticalfibers may also be used. The optical fiber core 196 operates as awaveguide through which the electromagnetic energy 102 travels. In oneembodiment, the nylon jacket 190 and at least a portion of the hardcladding 192 are removed from the distal end 130 of the optical fiber104 to expose the cladding 194 before attaching the fiber cap 134, asshown in FIG. 8. In one embodiment, the fiber cap 134 is attached to theoptical fiber 104 by fusing the fiber cap 134 to the optical fiber 104.In one embodiment, the fiber cap 134 is fused to the hard cladding 192and/or the cladding 194, as represented by element 186 in FIG. 8. In oneembodiment, the fiber cap 134 is adhered to the optical fiber 104 usinga suitable adhesive.

A distal tip 198 of the optical fiber core 196 may be formed to outputthe electromagnetic energy 102 as desired in accordance withconventional designs. For example, the distal tip 198 may comprise apolished beveled surface 200 that is non-perpendicular to a longitudinalaxis 202 of the optical fiber core 196. The beveled surface 200 operatesto reflect the laser light 102 laterally through a transmitting surface204 of the fiber cap 134, as shown in FIG. 8.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

1-20. (canceled)
 21. A system for cleaning a fiber cap comprising: afirst fixture configured to hold the fiber cap, the fiber cap having aninternal cavity with an opening therein, a first axis generally alignedwith a central axis of the fiber cap and internal cavity, a second axisorthogonal to the first axis, and a third axis orthogonal to the firstand second axes; a second fixture configured to hold a particulatecollecting member configured (1) to receive and hold an electricalcharge and (2) for insertion into the opening of the fiber cap; a firstcamera positioned to provide a view of the fiber cap held in the firstfixture and the particulate collecting member held in the second fixturein the direction of the third axis of the fiber cap; and a second camerapositioned to provide a view of the fiber cap held in the first fixtureand the particulate collecting member held in the second fixture in thedirection of the second axis of the fiber cap.
 22. The system of claim21, wherein the first fixture and the second fixture are adjustablealong the first, second and third axes.
 23. The system of claim 21,wherein the particulate collecting member comprises an electricalinsulator selected from the group consisting of glass, ceramic,porcelain and composite polymer materials.
 24. The system of claim 23,wherein the particulate collecting member is in the form of a rod, awire, or a fiber.
 25. The system of claim 21, wherein the electricalcharge is applied to the particulate collecting member by rubbing theparticulate collecting member with glass fibers or charging the memberwith an electronic device.
 26. A method of cleaning a fiber capcomprising: providing the system of claim 21; holding the fiber cap inthe first fixture; applying an electrical charge to the particulatecollecting member; holding the particulate collecting member in thesecond fixture; aligning a longitudinal axis of the particulatecollecting member with the central axis of the internal cavity of thefiber cap; and inserting the particulate collecting member through theopening and into the internal cavity of the fiber cap.
 27. The method ofclaim 26, wherein aligning the longitudinal axis of the particulatecollecting member with the central axis of the internal cavity of thefiber cap comprises viewing the fiber cap and the particulate collectingmember from two substantially orthogonal angles that are eachsubstantially orthogonal to the longitudinal axis of the particulatecollecting member and the central axis of the internal cavity of thefiber cap.
 28. The method of claim 27, wherein aligning the longitudinalaxis of the particulate collecting member to the central axis of theinternal cavity of the fiber cap comprises adjusting the relativepositions of the first and second fixtures.
 29. The method of claim 26,wherein inserting the particulate collecting member into the internalcavity of the fiber cap comprises moving the second fixture relative tothe first fixture along the central axis of the fiber cap.
 30. Themethod of claim 29, further comprising the step of attracting particleslocated within the internal cavity of the fiber cap to the particulatecollecting member after the particulate collecting member is insertedinto the internal cavity of the fiber cap.
 31. The method of claim 30,wherein: the particles have a first electrical charge; applying anelectrical charge to particle collecting member comprises applying asecond electrical charge to the particle collecting member that isopposite the first electrical charge; and attracting the particleslocated within the internal cavity to the particle collecting membercomprises electrostatically attracting the particles to the particlecollecting member.